For the 1961 Pontiac Tempest, the Saginaw 4-speed (or 3-speed) gearbox was moved to the rear by splitting the input gear, extending it with the world's most expensive driveshaft (8660 steel, carefully heat treated and every one Magnafluxed). It was 3/4" diameter and flexed in a long curve (almost 4" dip) going through a couple of guide bearings. The only other change was the shorter output shaft with splines that engaged internal splines in the hollow pinion shaft in the attached differential housing. A swing axle rear suspension completed the deal. This whole layout was the brainchild of some guy named John DeLorean.

The Corvair used the same gearbox and the Tempest differential housing but the input gear had to come from the rear. So both the pinion shaft and the gearbox output shaft (blue) are hollow... and the (24" long) input gear shaft (red) runs through them. Note that the gearbox is still facing the same direction as in th Nova and the Tempest... AND all the components inside are still turning the direction they designed for. Note also that the Corvair crankshaft is actually turning the same direction as the Nova and Tempest in the car (i.e. clockwise when viewed from the front of the car) but is considered a reverse rotation engine when viewed by convention.

After I had already started my conversion, I found out that it can be done differently to better distribute the weight. By rotating the entire engine/trans 180 deg so that the pulleys are at the back of the car, you can get a lot more of the weight in front of the rear axle. The differential housing then needs to be rotated 180 deg to an upside-down position to make the axles turn the opposite direction. This also places the pinion shaft below the axle centerline, effectively lowering the engine. I have never done a swap this way, so I can only speculate what changes must be made. First off, the tie rods can probably stay where they are. Also, the trunk may be able to be retained, or at least more of it. I would expect that the oil pan modification would be more extensive. If I were to do another longitudinal swap, I would definitely do a reverse rotation due to the weight distribution advantages.

The '66 & '67 Toro's also had the switch-pitch torque convertor in the 425 trans. The switch-pitch would be a slick set up for you; with the flip of a switch you can go from about 1400 stall speed to more like 2400. Maybe you already know all this stuff but you can convert a NON switch-pitch 425 to a switch-pitch.

325-4L

Used 1982-85 in Buick Riviera, Olds Toronado and Cadillac Eldorado.

This was an hydraulically controlled front wheel drive overdrive transmission with an electronically controlled lock-up torque converter .

Gear Ratios:
2.74:1 1st gear
1.57:1 2nd gear
1.00:1 3rd gear
0.70:1 4th gear
2.07:1 reverse

Called the TH425 in FWD form, the transmission's torque converterTorque converter was separated from its planetary gearset with the torque converter driving the gearset through a 2" wide silent chain-drive called Hy-Vo, riding on two 12" sprockets. The Hy-Vo chain drive was developed by GM's Hydra-Matic Division and Morse Chain Division of Borg-Warner. The chains were made from a very strong hardened steel and required no tensioners or idler pulleys because they were pre-stretched on a special machine at the factory. Although the rotation direction of the transmission's gearing had to be reversed, a large number of components were shared with the conventional TH400.